1. Field of the Invention
The present invention relates to a microscope including a transmitted-light illumination optical system for illuminating a specimen with transmitted light and a transmitted light source.
2. Description of the Related Art
As a typical microscope, an upright microscope including a transmitted-light illumination optical system and a transmitted light source, as disclosed in Japanese Patent Application Laid-open No. 2007-148364, is well-known. Such an upright microscope can be classified, for example, into five types as shown in FIGS. 11 to 15 (conventional examples 1 to 5). Microscopes according to the conventional examples 1 to 5 are described below with reference to FIGS. 11 to 15.
First, a configuration and a mechanism of the microscope according to the conventional example 1 are explained below with reference to FIG. 11.
As shown in FIG. 11, a main body 30 of the microscope according to the conventional example 1 has a C-shape when viewed from the side. The main body 30 is composed of a frame 18 and an arm 17. The frame 18 has an L-shape when viewed from the side. On the rear side (the left side in FIG. 11) of a base portion 18a of the frame 18, a halogen light source 1 as the transmitted light source is arranged.
An illumination light emitted from the halogen light source 1 enters a collector lens 3 contained in the base portion 18a of the frame 18, and is transformed into substantially parallel light by the collector lens 3, aid then illuminated onto a specimen 10 via a field stop (FS) 6, a mirror 7, a window lens 8, and a condenser lens 9. Specifically, the illumination light, which is transformed into the substantially parallel light by the collector lens 3, is collected on an aperture stop (AS) 9b by the window lens 8 and a first lens group 9a of the condenser lens 9, and uniformly illuminated onto the whole specimen 10 via a second lens group 9c of the condenser lens 9. The contrast of an image of the specimen 10 can be changed by changing an aperture diameter of the AS 9b. 
Furthermore, the illumination light passing through the FS 6 is transformed into substantially parallel light by the window lens 8 via the mirror 7, and collected on a plane of the specimen 10 (hereinafter, “the specimen plane”) by the condenser lens 9, and also an intermediate image of the FS 6 (hereinafter, “the FS image”) is projected onto the specimen plane. An illuminated region on the specimen plane (i.e., a field of view) can be changed by changing an aperture diameter of the FS 6.
The condenser lens 9 is removably held on a condenser holder 21 with a well-known means such as a circular dovetail (not shown). By rotation of a condenser handle 22, the condenser holder 21 is moved up and down, and thus the condenser lens 9 is moved up and down with respect to a stage holder 20 along with the condenser holder 21. The specimen 10 is put on a stage 19 held on the stage holder 20. Therefore, by moving the condenser lens 9 up and down, the FS image can be projected onto the specimen plane precisely.
A configuration of the halogen light source 1 is briefly explained below. The halogen light source 1 is contained in a lamp house 2. The lamp house 2 is removably held on the frame 18 of the main body 30 via a pin 2a. Incidentally, a power source 4 of the halogen light source 1 is contained in the frame 18, and capable of being electrically connected to the halogen light source 1 via the pin 2a. Furthermore, the collector lens 3, the FS 6, the mirror 7, and the window lens 8 are contained in the base portion 18a of the frame 18.
Subsequently, a basic configuration of an observation system of the microscope according to the conventional example 1 is explained below.
As shown in FIG. 11, the illumination light transmitted through the condenser lens 9 passes through the specimen 10, and is transformed into parallel light by an objective lens 11, and then focused into a specimen image by an imaging lens 14 provided in a tube 13 via a prism 15 and other prisms (not shown), whereby an observer can make a visual observation of the specimen image through an eyepiece lens 16. A plurality of the objective lenses 11 can be attached to a revolver 12 that is removably-held on the arm 17 of the main body 30. By rotation of the revolver 12, any of the objective lenses 11 having a desired magnification can be set on an optical path, so that an observer can make a visual observation of the specimen image at the desired magnification.
Subsequently, basic configurations of the focusing system and the stage of the microscope according to the conventional example 1 are explained below.
As shown in FIG. 11, the stage 19 is removably held on the stage holder 20. The stage holder 20 is removably held on a movable guide 23 capable of moving up and down. By rotation of a focusing handle 5, the movable guide 23 can be moved up and down with a well-known means such as a gear (not shown) or a rack and pinion (not shown). By the up-and-down movement of the movable guide 23, the specimen 10 put on the stage 19 can be moved up and down with respect to the objective lens 11 so as to adjust the focus.
When the specimen 10 is moved up and down by the rotation of the focusing handle 5, the condenser lens 9 is also moved up and down together with the specimen 10. On the other hand, the illumination light transmitted through the FS 6 is transformed into the parallel light by the window lens 8. Therefore, when the specimen 10 does riot greatly vary in thickness, it is not necessary to move the condenser lens 9 up and down anew by rotation of the condenser handle 22 to project the FS image onto the specimen plane.
Furthermore, the stage 19 on which the specimen 10 is put can be moved in an X direction (a direction perpendicular to the plane of the drawing in FIG. 11) and a Y direction (a horizontal direction in FIG. 11) by rotation of a stage handle (not shown). Therefore, an observer can find a desired observation point of the specimen 10 by rotating the stage handle.
With the microscope having the above configuration, an observer puts the specimen 10 on top of the stage 19, and focuses on the specimen 10 by rotating the focusing handle 5, and then finds a desired observation point of the specimen 10 by rotating the stage handle. Thus, the observer can make a visual observation of the specimen 10 at the desired observation point through the eyepiece lens 16.
Subsequently, a configuration and a mechanism of the microscope according to the conventional example 2 are explained with reference to FIG. 12.
The microscope according to the conventional example 2 is different from the microscope according to the conventional example 1 in that a filter is provided on the optical path of the illumination light. Except for this point, the description of the portions identical to those of the conventional example 1 is omitted.
As shown in FIG. 12, two filters 24 are removably inserted between the collector lens 3 and the FS 6 on the optical path of the illumination light. As the filters 24, for example, a color conversion filter and a neutral density filter are mainly used. The color conversion filter is used to increase a color temperature of a halogen lamp (not shown) thereby converting the color from reddish color into daylight color. The neutral density filter is used to adjust the brightness. Although the brightness can be adjusted by changing the voltage of the halogen lamp, if the voltage is changed, the temperature color is also changed. Therefore, the neutral density filter having uniform spectral transmission characteristics is generally used because there is no change in color temperature.
Subsequently, a configuration and a mechanism of the microscope according to the conventional example 3 are explained with reference to FIG. 13.
The microscope according to the conventional example 3 is different from the microscope according to the conventional example 1 in that a light-emitting diode (LED) light source 25 is included instead of the halogen light source 1. With the change of the light source, the power source for the light source is also changed to a power source 26 for the LED light source. Except for this point, the description of the portions identical to those of the conventional example 1 is omitted.
As described in the conventional example 2, when a halogen light source is used as the light source, it is necessary to provide a color conversion filter and a neutral density filter. However, in the microscope according to the conventional example 3, the LED light source 25 including an LED capable of emitting a light in daylight color is used. Therefore, it is not necessary to provide the color conversion filter. Furthermore, even when the voltage or the current of the LED is changed, there is little or no change in color temperature. Therefore, it is not necessary to provide the neutral density filter. In the conventional example 1, such filters are not provided even though the microscope employs the halogen light source. In a case where the color does not matter, it is not necessary to provide the filters, and thus it is possible to provide the microscope at a low cost.
Subsequently, a configuration and a mechanism of the microscope according to the conventional example 4 are explained with reference to FIG. 14.
The microscope according to the conventional example 4 is different from the microscope according to the conventional example 1 in that it is configured that the specimen plane is located at a lower position than that is in the conventional example 1. Except for this point, the description of the portions identical to those of the conventional example 1 is omitted.
As shown in FIG. 14, in the conventional example 4, a thickness of the stage holder 20 in a vertical direction is smaller than that is in the conventional example 1. Therefore, the stage holder 20 can be attached to the lower part of the movable guide 23. Thus, the specimen 10 comes down to a lower position. The stage 19 has the same thickness as that is in the conventional example 1.
Furthermore, in the conventional example 4, the condenser lens 9 also comes down to a lower position along with the stage holder 20. Therefore, in case of causing the first lens group 9a to interfere with the base portion 18a of the frame 18, the first lens group 9a is contained in the base portion 18a. With this, the window lens 8 and the FS 6 are shifted to the side of the halogen light source 1. By such a configuration, a position of the stage 19 on which the specimen 10 is put can be lowered. Thus, a room under the arm 17 gets larger than that is in the conventional example 1, so that replacement of the specimen 10 can be performed easily.
Subsequently, a configuration and a mechanism of the microscope according to the conventional example 5 are explained with reference to FIG. 15.
The microscope according to the conventional example 5 is different from the microscope according to the conventional example 1 in that a transmitted-light illumination optical system is configured to make an optical path straight without a mirror in place of the optical folding path with a mirror, and in that the LED light source is used as the transmitted light source instead of the halogen light source. Except for this point, the description of the portions identical to those of the conventional example 1 is omitted.
As shown in FIG. 15, the microscope according to the conventional example 5 includes the LED light source 25 instead of the halogen light source 1. With the change of the light source, the power source for the light source is also changed from the power source 4 for the halogen light source to the power source 26 for the LED light source. The LED light source 25 is arranged right below an observation optical axis. The illumination light emitted from the LED light source 25 is transformed into substantially parallel light by the collector lens 3, and collected on the AS 9b by the first lens group 9a via the FS 6, and focused into a light source image of the LED light source 25. In addition, the microscope according to the conventional example 5 does not include the window lens 8, and differs from the microscope according to the conventional example 1 in this point.
Furthermore, the illumination light passing through the FS 6 is collected on the specimen plane via the condenser lens 9, and an FS image is projected onto the specimen plane. Until the illumination light passing through the FS 6 enters the first lens group 9a, the illumination light is riot parallel light unlike in the conventional example 1. Therefore, if the illumination light is not focused on the specimen 10, the FS image is defocused significantly. The microscope according to the conventional example 5 is inferior in illumination performance as compared with the mirror folding type of microscope according to the conventional example 1. However, the microscope according to the conventional example 5 does not require the mirror 7 and the window lens 8, so that the production cost can be reduced. In addition, the LED light source 25 is arranged right below the observation optical axis, so that replacement of the LED light source 25 is relatively simple.